Netcdf Read and Plot

CRU_TR_Near-Surface_Temp_16-01-1901_16-12-2012_Monthly

R - NETCDF

CRU_TR_Near-Surface_Temp_16-01-1901_16-12-2012_Monthly

R - NETCDF

install.packages("ncdf4")
install.packages("RNetCDF")
install.packages("maptools")
install.packages("fields")

R Advance - ncdf4 Package

R Advance - ncdf4 Package

library(ncdf4)
ncdf4_open <- nc_open("cru_1901_2012_tmp_TR.nc")
ncdf4_open

## File cru_1901_2012_tmp_TR.nc (NC_FORMAT_CLASSIC):
## 
##      1 variables (excluding dimension variables):
##         double tmp[lon,lat,time]   
##             long_name: near-surface temperature
##             units: degrees Celsius
##             _FillValue: 9.96920996838687e+36
##             missing_value: 9.96920996838687e+36
##             correlation_decay_distance: 1200
## 
##      3 dimensions:
##         lon  Size:42
##             standard_name: longitude
##             long_name: longitude
##             units: degrees_east
##             axis: X
##         lat  Size:18
##             standard_name: latitude
##             long_name: latitude
##             units: degrees_north
##             axis: Y
##         time  Size:1344   *** is unlimited ***
##             standard_name: time
##             long_name: time
##             units: days since 1900-01-01 00:00:00
##             calendar: standard
## 
##     10 global attributes:
##         CDI: Climate Data Interface version 1.6.9 (http://mpimet.mpg.de/cdi)
##         Conventions: CF-1.4
##         history: Mon Feb 22 16:24:47 2016: cdo sellonlatbox,25,46,34,43 cru_ts3.21.1901.2012.tmp.dat.nc cru_1901_2012_tmp_TR.nc
## Wed 10 Jul 2013 17:04:15 BST : User ianharris : Program makegridsauto.for called by update.for
##         source: Run ID = 1307101324
## Data generated by BADC from:
## tmp.1307101049.dtb
##         institution: Data held at British Atmospheric Data Centre, RAL, UK.
##         title: CRU TS3.21 Mean Temperature
##         references: Information on the data is available at http://badc.nerc.ac.uk/data/cru/
##         comment: Data restrictions: for academic research use only.Contact BADC for details
##         contact: BADC <badc@rl.ac.uk>
##         CDO: Climate Data Operators version 1.7.0rc2 (http://mpimet.mpg.de/cdo)

R Advance - RNetCDF Package

R Advance - RNetCDF Package

library(RNetCDF)
rnetcdf_open <- open.nc("cru_1901_2012_tmp_TR.nc")
print.nc(rnetcdf_open)

## netcdf classic {
## dimensions:
##  lon = 42 ;
##  lat = 18 ;
##  time = UNLIMITED ; // (1344 currently)
## variables:
##  NC_DOUBLE lon(lon) ;
##      NC_CHAR lon:standard_name = "longitude" ;
##      NC_CHAR lon:long_name = "longitude" ;
##      NC_CHAR lon:units = "degrees_east" ;
##      NC_CHAR lon:axis = "X" ;
##  NC_DOUBLE lat(lat) ;
##      NC_CHAR lat:standard_name = "latitude" ;
##      NC_CHAR lat:long_name = "latitude" ;
##      NC_CHAR lat:units = "degrees_north" ;
##      NC_CHAR lat:axis = "Y" ;
##  NC_DOUBLE time(time) ;
##      NC_CHAR time:standard_name = "time" ;
##      NC_CHAR time:long_name = "time" ;
##      NC_CHAR time:units = "days since 1900-01-01 00:00:00" ;
##      NC_CHAR time:calendar = "standard" ;
##  NC_DOUBLE tmp(lon, lat, time) ;
##      NC_CHAR tmp:long_name = "near-surface temperature" ;
##      NC_CHAR tmp:units = "degrees Celsius" ;
##      NC_DOUBLE tmp:_FillValue = 9.96920996838687e+36 ;
##      NC_DOUBLE tmp:missing_value = 9.96920996838687e+36 ;
##      NC_DOUBLE tmp:correlation_decay_distance = 1200 ;
## 
## // global attributes:
##      NC_CHAR :CDI = "Climate Data Interface version 1.6.9 (http://mpimet.mpg.de/cdi)" ;
##      NC_CHAR :Conventions = "CF-1.4" ;
##      NC_CHAR :history = "Mon Feb 22 16:24:47 2016: cdo sellonlatbox,25,46,34,43 cru_ts3.21.1901.2012.tmp.dat.nc cru_1901_2012_tmp_TR.nc
## Wed 10 Jul 2013 17:04:15 BST : User ianharris : Program makegridsauto.for called by update.for" ;
##      NC_CHAR :source = "Run ID = 1307101324
## Data generated by BADC from:
## tmp.1307101049.dtb" ;
##      NC_CHAR :institution = "Data held at British Atmospheric Data Centre, RAL, UK." ;
##      NC_CHAR :title = "CRU TS3.21 Mean Temperature" ;
##      NC_CHAR :references = "Information on the data is available at http://badc.nerc.ac.uk/data/cru/" ;
##      NC_CHAR :comment = "Data restrictions: for academic research use only.Contact BADC for details" ;
##      NC_CHAR :contact = "BADC <badc@rl.ac.uk>" ;
##      NC_CHAR :CDO = "Climate Data Operators version 1.7.0rc2 (http://mpimet.mpg.de/cdo)" ;
## }

R Advance - ncdf4 VS RNetCDF

ncdf4_open <- nc_open("data.nc")
class(ncdf4_open)
str(ncdf4_open)
attributes(ncdf4_open)
attributes(ncdf4_open$dim)
attributes(ncdf4_open$var)
attributes(ncdf4_open$var$tmp)

ncdf4_open$var$tmp$longname
ncdf4_open$var$tmp$name
ncdf4_open$var$tmp

ncatt_get(ncdf4_open,'tmp')
ncvar_get(ncdf4_open,"tmp")
ncdf4_tmp <- ncvar_get(ncdf4_open,"tmp")

class(ncdf4_tmp)
dim(ncdf4_tmp)
str(ncdf4_tmp)

attributes(ncdf4_open)
attributes(ncdf4_open$dim)
ncdf4_lon <- ncvar_get(ncdf4_open, ncdf4_open$dim$lon)
ncdf4_lat <- ncvar_get(ncdf4_open, ncdf4_open$dim$lat)
ncdf4_time<- ncvar_get(ncdf4_open, ncdf4_open$dim$time)

rnetcdf_open <- open.nc("data.nc")
class(rnetcdf_open)
str(rnetcdf_open)

rnetcdf_read <- read.nc(rnetcdf_open)
class(rnetcdf_read)
str(rnetcdf_read)
attributes(rnetcdf_read)

var.get.nc(rnetcdf_open,'tmp')
rnetcdf_tmp <- var.get.nc(rnetcdf_open,'tmp')

class(rnetcdf_tmp)
dim(rnetcdf_tmp)
str(rnetcdf_tmp)

attributes(rnetcdf_open)
attributes(rnetcdf_read)

rnetcdf_lon <- var.get.nc(rnetcdf_open, "lon")
rnetcdf_lat <- var.get.nc(rnetcdf_open, "lat")
rnetcdf_time<- var.get.nc(rnetcdf_open, "time")

R Advance - ncdf4 Package

ncdf4_tmp <- ncvar_get(ncdf4_open,"tmp")
ncdf4_tmp[,,1]
ncdf4_tmp_first<- ncdf4_tmp[,,1]

image(ncdf4_lon, ncdf4_lat, ncdf4_tmp_first)

R Advance - ncdf4 Package

library("maptools")

turkey_shp <- readShapePoly("turkiye.shp")

image(ncdf4_lon, ncdf4_lat, ncdf4_tmp_first)

plot(turkey_shp, add = T)

R Advance - ncdf4 Package

library("fields")

image.plot( ncdf4_lon, ncdf4_lat, ncdf4_tmp_first, 
              xlab = "Lon", 
              ylab = "Lat", 
              main = "First Step (01-1901) Temperature for Turkey" )

plot(turkey_shp, add = T) 

apply(array1[,,index1],1:2,mean)

R - NETCDF

image.plot( ncdf4_lon, ncdf4_lat, 
            apply(ncdf4_tmp[,,1332:1344],1:2,mean) - apply(ncdf4_tmp[,,1:1331],1:2,mean), 
            xlab = "Lon", 
            ylab = "Lat", 
            main = "? for Turkey" )
         
plot(turkey_shp, add = T) 

R - NETCDF

image.plot( ncdf4_lon, ncdf4_lat, 
            apply(ncdf4_tmp[,,1332:1344],1:2,mean) - apply(ncdf4_tmp[,,1:1331],1:2,mean), 
            xlab = "Lon", 
            ylab = "Lat", 
            main = " 2012 VS Mean of 1901-2011 for Turkey" )
         
plot(turkey_shp, add = T) 

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